fix your ~/.ssh permissions

Ssh is very picky about permissions on the ~/.ssh directory and files. Sometimes you may do something to mess up these permissions. Run the following to fix most permissions problems. You may have to do this on both the remote host and local host.

    chmod 700 ~/.ssh

    chmod 600 ~/.ssh/id_rsa

    chmod 644 ~/.ssh/id_rsa.pub  

    chmod 644 ~/.ssh/authorized_keys

    chmod 644 ~/.ssh/known_hosts

Also no directory above ~/.ssh can have 'group' or 'other' write permissions.

http://blog.kristeraxel.com/2012/06/fix-your-ssh-permissions/